scholarly journals Estimation of Mean Radiant Temperature in Urban Canyons Using Google Street View: A Case Study on Seoul

2022 ◽  
Vol 14 (2) ◽  
pp. 260
Author(s):  
Eun-Sub Kim ◽  
Seok-Hwan Yun ◽  
Chae-Yeon Park ◽  
Han-Kyul Heo ◽  
Dong-Kun Lee
Keyword(s):  
Heat Stress ◽  
Spatial Patterns ◽  
High Density ◽  
View Factor ◽  
Mean Radiant Temperature ◽  
Street Canyons ◽  
Google Street View ◽  
Street Level ◽  
Street View ◽  
Radiant Temperature

Extreme heat exposure has severe negative impacts on humans, and the issue is exacerbated by climate change. Estimating spatial heat stress such as mean radiant temperature (MRT) is currently difficult to apply at city scale. This study constructed a method for estimating the MRT of street canyons using Google Street View (GSV) images and investigated its large-scale spatial patterns at street level. We used image segmentation using deep learning to calculate the view factor (VF) and project panorama into fisheye images. We calculated sun paths to estimate MRT using panorama images from Google Street View. This paper shows that regression analysis can be used to validate between estimated short-wave, long-wave radiation and the measurement data at seven field measurements in the clear-sky (0.97 and 0.77, respectively). Additionally, we compared the calculated MRT and land surface temperature (LST) from Landsat 8 on a city scale. As a result of investigating spatial patterns of MRT in Seoul, South Korea, we found that a high MRT of street canyons (>59.4 °C) is mainly distributed in open space areas and compact low-rise density buildings where the sky view factor is 0.6–1.0 and the building view factor (BVF) is 0.35–0.5, or west-east oriented street canyons with an SVF of 0.3–0.55. However, high-density buildings (BVF: 0.4–0.6) or high-density tree areas (Tree View Factor, TVF: 0.6–0.99) showed low MRT (<47.6). The mapped MRT results had a similar spatial distribution to the LST; however, the MRT was lower than the LST in low tree density or low-rise high-density building areas. The method proposed in this study is suitable for a complex urban environment consisting of buildings, trees, and streets. This will help decision makers understand spatial patterns of heat stress at the street level.

scholarly journals Application of Method for Calculating Sky View Factor Using Google Street View: Relation Between Sky View Factor and Physical Elements in Urban Space

2019 ◽  
Vol 2 ◽  
pp. 1-8
Author(s):  
Shoko Nishio ◽  
Fumiko Ito
Keyword(s):  
Urban Space ◽  
Computation Method ◽  
View Factor ◽  
Statistical Process ◽  
Google Street View ◽  
Sky View Factor ◽  
Street View ◽  
The Difference ◽  
Physical Elements

<p><strong>Abstract.</strong> We applied a computation method of calculating the sky view factor (SVF) using Google Street View to Shibuya area, Tokyo, for the purpose of examining the relation between the SVF/SVF change and physical elements. The distribution of the SVF calculated by the above method was visualized, and the statistical process showed the tendency of a high SVF in quasi-residential districts and roadsides of high-graded trunk roads. The difference in the SVF change was small at 10-m intervals. The SVF change tended to be more apparent near an intersection and at different elevations.</p>

scholarly journals Mean Radiant Temperature Measurements through Small Black Globes under Forced Convection Conditions

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 621
Author(s):  
Francesca Romana d’Ambrosio Alfano ◽  
Giorgio Ficco ◽  
Andrea Frattolillo ◽  
Boris Igor Palella ◽  
Giuseppe Riccio
Keyword(s):  
Heat Stress ◽  
Forced Convection ◽  
Response Times ◽  
Table Tennis ◽  
Mean Radiant Temperature ◽  
Metrological Analysis ◽  
Experimental Apparatus ◽  
The Mean ◽  
Globe Temperature ◽  
Radiant Temperature

One of the most critical variables in the field of thermal comfort measurements is the mean radiant temperature which is typically measured with a standard 150 mm black globe thermometer. This is also the reference instrument required for the assessment of heat stress conditions by means of the well-known Wet Bulb Globe Temperature index (WBGT). However, one of the limitations of this method is represented by the relatively long response time. This is why in recent years there has been a more and more pressing need of smart sensors for controlling Heating Ventilation and Air Conditioning (HVAC) systems, and for pocket heat stress meters (e.g., WBGT meters provided with table tennis balls). Although it is widely agreed that there is a clear advantage of small probes in terms of response times, their accuracy is a still a debated matter and no systematic studies aimed at metrologically characterizing their performances are actually available, due to the difficulty of reproducing measuring conditions such as a black enclosure at uniform temperature. In this paper the results of a metrological analysis of two small globes (38 and 50 mm diameter) carried out by means of an experimental apparatus specifically designed to reproduce a black uniform enclosure are presented and discussed. Experimental results revealed a systematic underestimation of the mean radiant temperature predicted by small globes of more than 10 °C in forced convection and at high radiative loads.

scholarly journals Measurement of the black globe temperature to estimate the MRT and WBGT indices using a smaller diameter globe than a standardized one: Experimental analysis

2019 ◽  
Author(s):  
Carlos Vargas-Salgado ◽  
Cristian Chiñas-Palacios ◽  
Jesús Aguila-León ◽  
David Alfonso-Solar
Keyword(s):  
Heat Stress ◽  
Human Performance ◽  
Mean Radiant Temperature ◽  
Measuring Device ◽  
Wet Bulb Globe Temperature ◽  
Margin Of Error ◽  
Globe Temperature ◽  
Radiant Temperature ◽  
Performance Behavior ◽  
Black Globe Temperature

Heat stress can affect negatively human performance, behavior and even health, therefore, mean radiant temperature (MRT) and wet-bulb globe temperature (WBGT) measurement and monitoring should be obtained for any environment in which people are constantly exposed. The aim of this work is to compare the globe thermometer temperature (tg), used for calculating both MTR and   WBGT, using a smaller globe compared to a standardized diameter. For such purpose, a prototype has been designed. The device consists of an Arduino MEGA board, three temperature sensors, two black globes (Copper globe, matt black painted) and an anemometer. As an effort to use a device with a globe easier to handle in a real measuring device, a 9 cm diameter globe has been used which has a smaller diameter than a standardized one (15 cm); the third temperature sensor is used to measure the air temperature. MRT monitoring tests were carried out using the proposed prototype,  collected data were compared between the smaller and the standardized diameter globes measurements according to UNE EN ISO 7723 and NTP 322 recommendations. Results of this work show that it is possible to use a smaller diameter globe in a heat stress monitor, with an acceptable margin of error compared to a standardized size globe.

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